The short answer
They are two different stones. A lab grown diamond is diamond. Moissanite is silicon carbide. Moissanite throws noticeably more coloured fire, costs considerably less, and is slightly softer — though still hard enough for daily wear.
How they look
Side by side, the difference is in the flashes. Diamond returns mostly white light with restrained coloured sparkle. Moissanite has a higher dispersion, so it throws stronger rainbow flashes, particularly in direct sunlight and in larger sizes. Below about half a carat the two are hard to tell apart without training. Above two carats, most people can see the difference in the right light.
Whether that is a drawback depends entirely on taste. Plenty of people prefer the extra fire.
Hardness
Diamond is 10 on the Mohs scale. Moissanite is about 9.25 — harder than sapphire, harder than anything it is likely to meet in daily life. Both are suitable for an everyday ring. Neither will scratch from normal wear.
Price
Moissanite is the least expensive of the three options by a wide margin, lab grown diamond sits in the middle, mined diamond is the most expensive. For a two carat centre stone the gap between moissanite and lab grown diamond is substantial — enough to fund a better setting, a wider band, or a matching wedding ring.
Certification
Our moissanite is GRA certified and graded D colour, VVS1 clarity as standard. Our lab grown diamonds are GIA or IGI certified. Both certificates state the stone type plainly — moissanite is never described as a diamond.
Which should you buy?
- Choose lab grown diamond if the word diamond matters to you, if you want the restrained white sparkle of diamond, or if the piece is an engagement ring and that distinction is important to the person wearing it.
- Choose moissanite if you want the largest, brightest stone your budget allows, if you like strong coloured fire, or if you want a piece you can wear without worrying about it.
What they have in common
Both are lab created, both avoid mining entirely, and both are set here in solid gold rather than plated base metal. Whichever stone you choose, the metal around it is the same.